The field of the present invention is well drilling equipment and processes.
In drilling operations in water environments such as undersea oil drilling, well leakage can be a critical problem. This also may be true regarding leakage between zones even in more conventional drilling operations. To avoid any problem of this sort, well cement is frequently employed to insure against such events.
When drilling to a productive zone, a casing is employed to line the wall of the well. The casing typically does not extend through the productive zone. Rather, when needed, a liner is positioned to extend downwardly in the well from the casing. A mechanism for sealing the upper end of the liner to the bottom portion of the casing is illustrated in U.S. Pat. No. 5,052,483 for a sand control adapter, the disclosure of which is incorporated herein by reference. Even with the seal, the well may be cemented around the periphery of the liner.
The process of placing and cementing a liner for the completion of a well has typically required multiple trips down the well to drill the bore, place, cement, seal and clear the liner. The liner may be drilled in or separately positioned. When the liner is drilled in, a drilling bit is positioned on the lower end of the liner. Some means for applying torque through the liner to the drilling bit is then necessary.
Cementing a well involves the introduction of cement into the well and down through the positioned liner. Through use of a wiper plug backed by fluid, the volume of cement previously introduced to the well is forced down and out of the bottom of the liner where it flows upwardly around the annular space outwardly of the liner. In cementing a liner, crews have found it advantageous to either oscillate the liner axially or rotationally to enhance cement flow. Thus, during cementing, some means for again providing forced driving of the liner is considered advantageous. Sealing and hanging the liner within the casing is typically also performed.
The steps necessary for such well completion have typically required multiple trips into the well. A desire to limit the number of trips into the well has existed. Schemes for gravel packing wells and the like with a single placement of drilling tools have been used. Reference is made to U.S. Pat. No. 5,253,708 for PROCESS AND APPARATUS FOR PERFORMING GRAVEL-PACKED LINER COMPLETIONS IN UNCONSOLIDATED FORMATIONS and U.S. Pat. No. 5,255,741 for PROCESS AND APPARATUS FOR COMPLETING A WELL IN AN UNCONSOLIDATED FORMATION, the disclosures of which are incorporated herein by reference.